I have managed to port the arduino IR library by Ken Shirriff to esp8266 using the Sming framework. It can encode and decode. The sending uses bit-banging rather than PWM since I could not get it to work consistently. I have tested using a NEC remote and checked the codes using an Arduino with IRremote. I will be updating the documentation over the next few days.
https://github.com/sh4d0w12/esp8266_IRremote